Actually, he did essentially say the first thing, because he directly stated that Nuparu's personality is dependent upon his gender, meaning that his character traits are dependent upon his gender, and thus meaning that characteristics like inventiveness are related to masculinity. Now, I don't think he MEANT to say this, but that is how the writing of his post went.
Also, how does having multiple character traits force one into a certain gender, especially since we've already established that various character traits can exist in both genders? If there is a certain character trait that exists in Nuparu that absolutely, 100% necessitates him being a male, then fine, he stays a male. And, just to satisfy your belief that people haven't "paid much attention to him," here are the traits BS01 lists him as having:
"Nuparu is a master engineer, and feels at ease when surrounded by machinery he can tinker with, continuing this passion even as a Toa. He also has a great passion for learning, and saw being a Toa as an opportunity to explore new places and study new things and creatures. While this fascination could sometimes distract him from the task at hand, Nuparu's resourcefulness saved his friends many times over."
Now, which of these traits is necessarily masculine? Mastery at engineering? No. Passion for learning? No. Desire to explore new places and study new things and creatures? No. Sometimes getting distracted by your interests and hobbies? No. Resourcefulness? No.
I'm not saying that Nuparu MUST be gender-swapped in G3--none of us are, I think. What I AM saying is that trying to determine gender based upon character traits does not work, because there are very few traits that are definable as masculine or feminine, and even those that are do not show up all that often in BIONICLE characters.